1 files changed, 26 insertions, 0 deletions
diff --git a/crates/typst-utils/src/lib.rs b/crates/typst-utils/src/lib.rs
index b59fe2f7..34d6a943 100644
--- a/crates/typst-utils/src/lib.rs
+++ b/crates/typst-utils/src/lib.rs
@@ -31,6 +31,7 @@ use std::ops::{Add, Deref, Div, Mul, Neg, Sub};
 use std::sync::Arc;
 
 use siphasher::sip128::{Hasher128, SipHasher13};
+use unicode_math_class::MathClass;
 
 /// Turn a closure into a struct implementing [`Debug`].
 pub fn debug<F>(f: F) -> impl Debug
@@ -337,3 +338,28 @@ pub trait Numeric:
     /// Whether `self` consists only of finite parts.
     fn is_finite(self) -> bool;
 }
+
+/// Returns the default math class of a character in Typst, if it has one.
+///
+/// This is determined by the Unicode math class, with some manual overrides.
+pub fn default_math_class(c: char) -> Option<MathClass> {
+    match c {
+        // Better spacing.
+        // https://github.com/typst/typst/commit/2e039cb052fcb768027053cbf02ce396f6d7a6be
+        ':' => Some(MathClass::Relation),
+
+        // Better spacing when used alongside + PLUS SIGN.
+        // https://github.com/typst/typst/pull/1726
+        '⋯' | '⋱' | '⋰' | '⋮' => Some(MathClass::Normal),
+
+        // Better spacing.
+        // https://github.com/typst/typst/pull/1855
+        '.' | '/' => Some(MathClass::Normal),
+
+        // ⊥ UP TACK should not be a relation, contrary to ⟂ PERPENDICULAR.
+        // https://github.com/typst/typst/pull/5714
+        '\u{22A5}' => Some(MathClass::Normal),
+
+        c => unicode_math_class::class(c),
+    }
+}